Post-cardiac arrest level of free-plasma DNA and DNA-histone complexes

Plasma DNA-histone complexes and total free-plasma DNA have the potential to quantify the ischaemia-reperfusion damages occurring after cardiac arrest. Furthermore, DNA-histone complexes may have the potential of being a target for future treatment. The aim was to examine if plasma DNA-histone complexes and the levels of total free-plasma DNA were elevated in post-cardiac arrest patients compared with healthy individuals, and to examine if these biomarkers were capable of predicting mortality.

We included 42 comatose out-of-hospital cardiac arrest patients and collected blood samples after 22, 46 and 70 h. Samples for DNA-histone complexes were quantified by Cell Death Detection ELISA^plus . The total free-plasma DNA analyses were quantified with qPCR by analysing the Beta-2 microglobulin gene. The control group comprised 40 healthy individuals.

We found no difference in the level of DNA-histone complexes between the 22-h sample and healthy individuals (P = 0.10). In the 46-h sample, there was an increased level of DNA-histone complexes in non-survivors compared with survivors 30 days after the cardiac arrest (P < 0.01) and the area under the ROC curve was 0.78 (95% confidence interval: 0.59;0.96). The level of total free-plasma DNA was increased in the 22-h sample compared with healthy individuals (P < 0.001) but no significant difference was found between non-survivors and survivors 30 days after the cardiac arrest (all P ≥ 0.06).

An increased level of DNA-histone complexes was associated with increased mortality and that the level of total free-plasma DNA was elevated post-cardiac arrest.